IAN Blackford accused Tory leadership contender Boris Johnson of making "a career out of lying" in a rowdy Prime Minister's Questions session. 

Tories shouted down the SNP Westminster leader as he took aim at both of the men competing to become the next prime minister. 

After Theresa May was unable to answer whether she would pledge not to vote for a successor who would plunge the UK into a "devastating no-deal Brexit", Blackford slammed Boris Johnson and Jeremy Hunt. 

Blackford said: "The Prime Minister is showing gross cowardice. On the one hand, Tories are asking people to put their faith in the most incompetent foreign secretary in a century. A man who has made a career out of lying, who has spent his week avoiding the media, staging photos and playing to the extreme delusions of the Tories.

"On the other hand, we have the most incompetent health secretary in our history. A man who writes books on privatising our NHS, Mr Speaker, the Conservatives clearly don’t like the truth. Someone so desperately … [inaudible as Tories shout over Blackford]"

READ MORE: Boris Johnson branded a racist by Ian Blackford at PMQs

On Twitter, some praised Blackford, while others hit out at the Speaker for allowing the Tories to drown out the SNP MP for so long. 

Last week, Blackford infuriated Tories when he described Johnson as a racist. 

John Bercow warned Blackford to be "extremely careful in the language he uses".